International audience

Organophosphate flame retardants (PFRs) can be rapidly metabolized in the body, and recent studies have shown that the di-alkyl phosphates (DAPs) are important metabolites. The accumulation and distribution of 8 PFRs and their 4 DAPs metabolites were first investigated in whole-body samples and various tissues of three freshwater fish species (topmouth gudgeon, crucian carp and loach) with different feeding habits from locations around Beijing, China. Concentrations of ΣPFRs in whole-body samples across all sampling locations ranged from 264.7 to 1973 ng g−1 lipid weight (lw), while all the paired DAP metabolites were detected in the total range from 35.3 to 510 ng g−1 lw. The calculated log bioconcentration factors (BCFs) of PFRs in whole fish were correlated with their log KOW (P < 0.05). The metabolite/parent ratios (MPRs) of ΣDAPs were calculated and ranged from 0.10 to 1.12 in whole-fish of all species. The MPRs of BBOEP/TBOEP were the highest. With respect to their distribution in different tissues, both the parent PFRs and metabolites were found at relatively higher levels in the liver than in other tissues (muscle, intestine, kidney and ovary), which was markedly different from those observed in avian species in previous studies. The accumulation of PFRs and DAPs in various tissues was not significantly correlated with the lipid content. The highest PFRs level in the liver may be related to the active hepatic accumulation processes. Meanwhile, the MPRs for all 4 pairs were the highest in the kidney relative to the other tissues. To the best of our knowledge, this is the first study of DAPs in the wild animals, and our study may improve the understanding of the accumulation and metabolism of PFRs in the body.

Samples of lichens, snow and particulate matter (PM10, 24 h) are used for the source identification of air pollution in the heavily industrialized region of Ostrava, Upper Silesia, Czech Republic. An integrated approach that uses different environmental samples for metal concentration and Pb isotope analyses was applied. The broad range of isotope ratios in the samples indicates a combination of different pollution sources, the strongest among them being the metallurgical industry, bituminous coal combustion and traffic. Snow samples are proven as the most relevant indicator for tracing metal(loid)s and recent local contamination in the atmosphere. Lichens can be successfully used as tracers of the long-term activity of local and remote sources of contamination. The combination of PM10 with snow can provide very useful information for evaluation of current pollution sources.

Arsenic (As) in soils is of major environmental concern due to its ubiquity and carcinogenicity. Pteris vittata (Chinese brake fern) is the first known As-hyperaccumulator, which is highly efficient in extracting As from soils and translocating it to the fronds, making it possible to be used for phytoremediation of As-contaminated soils. In addition, P. vittata has served as a model plant to study As metabolisms in plants. Based on the recent advances, we reviewed the mechanisms of efficient As solubilization and transformation in rhizosphere soils of P. vittata and effective As uptake, translocation and detoxification in P. vittata. We also provided future research perspectives to further improve As hyperaccumulation by P. vittata.

Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation.

This study aimed at assessing the effects of increased air temperature and reduced soil moisture content on the multi-generation toxicity of a soil polluted by metal/metalloid mining wastes. Enchytraeus crypticus was exposed to dilution series of the polluted soil in Lufa 2.2 soil under different combinations of air temperature (20 °C and 25 °C) and soil moisture content (50% and 30% of the soil water holding capacity, WHC) over three generations standardized on physiological time. Generation time was shorter with increasing air temperature and/or soil moisture content. Adult survival was only affected at 30% WHC (∼30% reduction at the highest percentages of polluted soil). Reproduction decreased with increasing percentage of polluted soil in a dose-related manner and over generations. Toxicity increased at 30% WHC (>50% reduction in EC50 in F0 and F1 generations) and over generations in the treatments at 20 °C (40–60% reduction in EC50 in F2 generation). At 25 °C, toxicity did not change when combined with 30% WHC and only slightly increased with 50% WHC. So, higher air temperature and/or reduced soil moisture content does affect the toxicity of soils polluted by metal/metalloid mining wastes to E. crypticus and this effect may exacerbate over generations.

Volatile organic compounds (VOCs) emissions from the chimney of a prevailing domestic stove fuelled with raw bituminous coal were measured under flaming and smoldering combustion processes in a farmer's house. The results indicated that the concentrations of VOCs quickly increased after the coal loading and achieved their peak values in a few minutes. The peak concentrations of the VOCs under the smoldering combustion process were significantly higher than those under the flaming combustion process. Alkanes accounted for the largest proportion (43.05%) under the smoldering combustion, followed by aromatics (28.86%), alkenes (21.91%), carbonyls (5.81%) and acetylene (0.37%). The emission factors of the total VOCs under the smoldering combustion processes (5402.9 ± 2031.8 mg kg⁻¹) were nearly one order of magnitude greater than those under the flaming combustion processes (559.2 ± 385.9 mg kg⁻¹). Based on the VOCs emission factors obtained in this study and the regional domestic coal consumption, the total VOCs emissions from domestic coal stoves was roughly estimated to be 1.25 × 10⁸ kg a⁻¹ in the Beijing-Tianjin-Hebei region.

Rigorous studies on long-term changes of heavy metal distribution in forest soils since the implementation of emission controls are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area) and foliar chemistry from three decades ago. It was hypothesized that declining deposition of heavy metals is reflected in soil and foliar total contents of Pb, Cu, Zn, Ni, Mn and Fe. Mean soil contents of Pb in the stemflow area declined at the highest rate from 223 to 50 mg kg−1 within the last three decades. Soil contents of Pb and Ni decreased significantly both in the stemflow area and the between trees area down to 80–90 cm soil depth from 1984 to 2012. Top soil (0–5 cm) accumulation and simultaneous loss in the lower soil over time for the plant micro nutrients Cu and Zn are suggested to be caused by plant uptake from deep horizons. Reduced soil leaching, due to a mean soil pH (H2O) increase from 4.3 to 4.9, and increased plant cycling are put forward to explain the significant increase of total Mn contents in the infiltration zone of beech stemflow. Top soil Pb contents in the stemflow area presently exceed the critical value at which toxicity symptoms may occur at numerous sites. Mean foliar contents of all six studied heavy metals decreased within the last three decades, but plant supply with the micro nutrients Cu, Zn, Mn and Fe is still in the optimum range for beech trees. It is concluded that heavy metal pollution is not critical for the studied beech stands any longer. Microsites, affected by beech stemflow, are very useful for studying the legacy of high atmospheric heavy metal deposition.